1. Field of the Invention
This invention relates to a magneto-optical recording medium for use in a magneto-optical memory, magnetic printing, a display element, etc. and to a magneto-optical information reproducing system for reading out information recorded on such a medium by the use of the magneto-optical effect such as a magnetic Kerr effect or the Faraday effect.
2. Related Background Art
Magneto-optical recording mediums for effecting read-out by the utilization of the magneto-optical effect, are known using polycrystal thin films such as MnBi or MnCuBi, non-crystalline thin films such as GdFe, GdCo, TbFe, DyFe, GdTbFe, TbFeCo, TbDyFe, GdTbCo, GdTbFeCo, GdTbFeGe, TbFeCoBi or TbSmFeCo, or single crystal thin films such as GdIG or GdBiIG. Of these thin films, said non-crystalline thin films have recently been considered to be excellent for use as magneto-optical recording mediums when the film forming property with which a large area of thin film is made and the writing efficiency for writing signals with small photo-thermal energy are taken into account.
However, such a known magneto-optical recording medium has suffered from a problem. Because the aforementioned magneto-optical effect is small, the C/N (carrier signal/noise) ratio when information is reproduced is small. To solve such a problem, there have heretofore been proposed mediums in which an anti-reflection layer is provided on the light incidence side of the magnetic recording layer or in which a light reflecting layer or a light interference layer and a light reflecting layer are provided on that side of the magnetic recording layer which is opposite to the light incidence side (for example, U.S. Pat. No. 4,466,035, etc.).
However, even in the mediums as described above, no detailed analysis has been made about the specific structure such as film thickness, and the best use of the characteristic features of the mediums has not been made.